Io qui proverei a fare un ulteriore controllo:

function PlayFlashMovie()
{
shoh('Layer2');
var flashMovie=getFlashMovieObject("myFlashMovie");
flashMovie.Play();
}

cioè:

function PlayFlashMovie()
{
shoh('Layer2');
if (document.getElementById) { // DOM3 = IE5+, NS6+, FF
if (document.getElementById('Layer2').style.display = 'block' ) {
var flashMovie=getFlashMovieObject("myFlashMovie");
flashMovie.Play();
}
} else {
if (document.layers) { // NS4.7
if(document.Layer2.display = 'block') {
var flashMovie=getFlashMovieObject("myFlashMovie");
flashMovie.Play();
}
}
}
else { //IE 4
if (document.all.Layer2.style.display = 'block') {
var flashMovie=getFlashMovieObject("myFlashMovie");
flashMovie.Play();
}
}
}


^^